The present invention relates generally to a limit switch gauging apparatus and more particularly to a machine tool limit switch gauging positioner for carrying out various machine functions.
Various adjustable positive stop or micrometer stop devices have been employed in an effort to halt the movement of a machine tool at an exact location upon the completion of its forming operation. The present invention is particularly concerned with a limit switch positioner means for controlling and measuring the depth of holes by a machine tool such as, for example, in an electric or spark discharge machining process referred to generally as an EDM process.
EDM machines are used to form holes of varied shapes in materials of poor machinability and to form cavities in steel dies. To attain high surface quality and accuracy, it is essential that small gaps or spaces be maintained between the cutting tool or cathode and the work piece or anode. The gaps are essential as they are filled with a dialectric hydrocarbon oil cooling medium which flushes away metal particles. The electrode cutting tool is advanced by a machine carriage, usually in the form of a vertically reciprocal ram member, by means of an electrical servo mechanism which controls and maintains the rate of feed and proper gap size. In this manner, cavities from a few 1000ths of an inch to two or three inches in width may be machined by this process. Although EDM machines have found remarkable success in the machine tool industry, it has been a particular problem to control the depth of holes or blind bores maintaining a desired gap between the electrode and the work.
It is an object of the present invention to provide an adjustable positive stop limit switch gauging or measuring apparatus which may be readily added to an existing machine.
Another object of the present invention is to provide a limit switch positioner apparatus wherein a cutting tool or a machine ram or the like may be automatically halted at the finish of its forming operation at an exact location relative to the work piece assuring the accurate formation of holes, cavities, etc.
A further object of the invention to provide a limit switch gauging positioner apparatus for an electric-discharge machine having an adjustable micrometer stop assuring that there is no physical contact between the electrode tool and the workpiece while providing high quality and accuracy.